Desuperheater



Jan. 17 1933. a w R DORF 1,894,791

'DESUPERHEATER Filed Aug. 1, 1931 2 Sheets-Sheet l lNVENTOR ATTORN EYJan. 17, 1933. w, R'UDQRFF 1,894,791

DESUPERHEATER Filed Aug. 1, 1931 2 Sheets-Sheet 2 4.4 III IIIIIII III!ii? Iiiii ATTORN EY Patented Jan. 17, 1933 DAGOBERT W. RUDGRFF, 0F EEKYORK, ."cl'. Y., ASSIGNOE TO THE SUPERHEATER GCMEAHY, 8F NEW 5503K, N.Y.

DEfiUlEREEATEB .Appiicatieu filed August 1, 1931.

This invention relates to the art of desuperheating steam and relatesmore particularly to the case where superheated steam of high pressureis to be changed to desuperheated steam of considerably lower pressure.

The particular form of the apparatus used in the invent-ion isimmaterial except that it must be apparatus in which the steam does notcome into direct contact with the desuperheating agent. Ordinarily thisdesuperheating agent will be Water, this water being in a casing throughwhich pipes extend containing the steam to be treated.

My invention has for its purpose to provide improved apparatus for andan improved method of treating steam in the manner and for the purposeindicated.

The high pressure steam under the conditions to which my inventionrelates is to be changed to steam of the lower pressure. This iseffected by means of a reducing valve. Two arrangements can be used, andin practice have been used. The reducing valve may either be arranged inadvance of the desuperheating apparatus or it may follow such apparatus.Under some conditions one or the other of these arrangements issatisfactory. There are, however, cases where neither of these oldarrangements can be used. Suppose, for example, we have steam of iOOqqEpressure and 775 deg. F. total temperature which is to be changed tosaturated steam at pressure. Assume further that the pressure in thewater space is 401 i, which would be the usual situation making itpossible to add the steam generated in the desup-erheater to thedesuperheated low-pressure steam. It the reducing valve is placed at theoutlet of the desuperheating apparatus, and the steam is reduced tosaturation in the desuperheater before being expanded to the 40 pressurein the reducing valve, the steam after such pressure reduction will havea temperature of 33% or 67 degrees superheat. The desired result ofhaving saturated steam at 40a pressure is therefore not obtained. Onecould of course condense a part of the high pressure steam and therebyob tain saturated low pressure steam after expansion through thereducing valve. This,

Serial No. 554,452.

however, is a very unsatisfactory procedure largely because of thedanger of injurying the reducing valve and the possibility of carryingwater over into the low pressure apparatus.

If on the other hand the reducing valve is placed ahead of thedesuperheating appara tus, then the steam at 40$]: pressure will have atemperature much nearerthe temperature of the desuperheating water andthe heat so transfer will be less efiicient with the result than anunreasonably large desuperheater will be required.

my arrangement, apparatus is provided which is neither unreasonablylarge as under the second arrangement mentioned above nor has thedisadvantages or impossibilities inherent in the first arrangement.Briefly, my arrangement includes a two-stage desuperheater with theexpansion valve between them. Steam at the original high pressure isdesupei'heated in the first stage substan tially down to its saturationtemperature, or some other suitable temperature above this point, isthen expanded to the lower pressure in the expansion valve, and thendesuper- I heated to saturation temperature or other desired point abovesaturation temperature in the second stage of the desuperheater.Preferably, the two desuperheater sections are arranged in the samecasing, the desuperheating tubesbeing immersed in the same b'oc y ofwater although this is optional.

1 illustrate my invention in the-drawings on the accompanying sheetswhere Fig. 1 represents a horizontal section on line 1-1 of Fig. 2, Fig.2 shows an external prospective view on a smaller scale o1 theapparatus, and Fig. 3 shows a vertical central section on line 33 ofFig. 1.

The outer cylindrical casing 1 has its lower end closed by the hollowheader 2 and has at its upper end an outlet 3. The space within thecasing 1 is filled to the desired point with water which is supplied asrequired through the connection 4:. as is a connection for avsafetyvalve. The inside of the header 2 is divided into the tourchambers 2a, 2b, 20 and 256' by the partitions 26, 2f, 2g, and 27a. Aconnection 5 communicates with space 2a; a connection 6 communicateswith space 26; a connection 7, with space 2d and a connection 8, withspace 20. The connections 6 and 7 are in turn connected to each other bymeans of the pipe 9 and pressure reducing valve 10, the latter being ofany usual or preferred type. Rolled into the upper plate 11 of theheader 2 are the lower ends of a plurality of tubes of inverted U-shape.One set of these, 12a, connects the two spaces 20 and 2d, and the otherset, 12?), connects the two s aces 2a and 21). Both sets extend. upwardinto the space inside of the drum 1. Opposite the lower ends of thetubes 12a and 121) are openin s 13-13 through which tools can be insertefor rolling the tubes in. These openings are closed by means of handhole covers when the apparatus is in use.

The operation of the apparatus 5 s as follows: lVater' is filled intothe shell 1 to the desired height. The superheated hi h-pressure steamis admitted through the connection 5. It flows through the tubes 1% fromchamber 2a to chamber 27). The water on the outside of the tubes 12?)desuperheats the steam. Preferably the apparatus is so designed that todo this at the pressure preveiling in the drum the water level is abovethe up an ends of the tubes 1%, although the design may be such that thelevel stands below such point. This desuperheated steam is next allowedto flow through connection 6 and pipe 9 to the expansion valve 10 whereit ex ands to the lower pressure. The result will be lower pressuresteam of a degree of superheat depending upon the amount of expansion.This superheated steam is next carried through connection '7 to flowthrough the pipes 12a where either all or the desired part of thesuperheat is removed, after which the steam is taken through connection8 to the point of use. The amount of desuperheating in the tubes 12a canbe accurately determined by the design.

It will be noted in the illustrative example shown in the drawings thatthe number of inverted U-shape tubes 1% is considerably smaller than thenumber of inverted U-shape tubes 12a. The actual relative numbers ofthese two will of course depend upon conditions such as the initial andfinal pressures, the initial temperature, and the final temperaturedesired. In any case, however, the total of the two will be cut down bymy ar rangement by a large amount as compared with the total that wouldbe required if the expansion valve were placed at the inlet of theapparatus.

As stated above, I prefer the arrangement in which both sets of tubesare placed in a common desuperheating casing, but it will be obviousthat in some cases it might be desirable to have them in. separatecasings. Moreover the desuperheating might be done in more than twostages with expansion valves between successive stages. These and othervariations are clearly within the scope of my invention and are meant tobe included within the appended claims.

I claim:

1. In the art of steam treatment the process of changing high-pressuresuperheated steam to low-pressure desuperheated steam comprising thesteps of first abstracting a large part of the super-heat, then allowingthe steam to expand to the lower pressure whereby it again becomes morehighly superheated, and then finally reducing the superheat to thedesired point.

2. In the art of steam treatment the process of changing high-pressuresuperheated steam to low-pressure desuperheated steam comprising thesteps of first removing substantially all of the superheat, thenreducing the pressure thereby again raising the superheat, and finallyagain desuperheating the steam by the desired amount.

3. Desuperheating apparatus including a stage in which high-pressuresuperheated steam is desuperheated by water in heat-exchanging relationbut out of contact with the steam, a low pressure stage in whichlowpressure superheated steam is desuperheated by water inl1eat-e:-:ehanging relation but out of contact with the steam, apressure reducing valve, and connections to the high-pressure stageinlet, from the high pressure stage outlet to the valve, from the valveto the low pressure stage, and from the low pressure stage.

4. Apparatus in accordance with claim 3, a single drum containing thewater for both desuperheating stages.

5. A desuperheater comprising a vertical cylindrical casing, afour-chambered header closing it at the bottom, two sets of invertedU-shaped elements secured to the header wall and extending into thecylindrical casing the first set connecting the header chambers inpairs, an inlet to one chamber of the first pair, a conduit including apressure reducing valve connecting the second chamber of the first pairto a chamber of the second pair, and an outlet from the other chamber ofthe second pair.

DAGOBERT V. RUDORFF.

